The present disclosure relates to a computer graphics system, and more particularly, to displaying updates to digital ink.
Digital ink allows a user to draw on a screen of a display device using a device such as a digitized pen. Typically, the input from the device generates a command from the CPU to update the screen to include the digital ink. The screen update is provided to a graphics processor (GPU) that renders the updated screen including the digital ink. The GPU typically queues the digital ink along with other updates to the screen and renders the ink when the screen is updated. Typical screen refresh rates are on the order of 30-90 Hz. A user may move a digital pen tip at high speeds (relative to the screen refresh rate) with rapid changes in direction. For example, a digital pen may provide position updates at 240 Hz. Due to the length of the rendering pipeline, there may be a delay of at least 50 ms between the time an input of digital ink is received to the time that the GPU is able to render the input. Accordingly, when drawing with digital ink, a user may notice a gap between the tip of the pen input and the rendered digital ink. The user may feel the experience of drawing with digital ink is less responsive than traditional ink. In the case of specialized digital ink having more detailed features such as pencil effects, the gap between the tip of the pen input and the rendered digital ink may reduce feedback to the user regarding the detailed features of the digital ink.
One solution to processing digital ink is to use customized processing hardware in the display device that processes the input and renders the digital ink. For example, the display device may detect the location of a pen and shade pixels using the customized processing hardware. While effective, this solution is customized to specific hardware and the customized processing hardware adds significant cost.
Thus, there is a need in the art for improvements in graphics processing for updating digital ink on display devices.